Recently a friend and I took an afternoon to play at dying with woad. I was really hoping to have more success than my last attempt. I prepped and planned to attempt dying with woad using three different techniques.
Fresh leave that were fermented in water
Roughly 300gms of fresh leaves were washed and then chopped and placed in a tub with fresh water. The tub was then set inside a cooler with more fresh water and a fish tank heater to keep it at a temperature of 30C. After a couple of days soda ash was added to change the ph (to about 9).
It was then left for a week.
Before trying to dye we poured the fermented fate into a dye pot and strained out the goop. We then warmed it up until it was hot to the touch and not boiling. A swatch of cream wool and a small test skein of yarn were soaked in water and then place in the dye pot. It was left for an hour.
Taken out and then exposed to air we were disappointed that it didn’t magically turn blue. Instead it became more of a tan colour. So at least it had some change in colour, just not the one that we were hoping for. It’s possible more working with this vat may produce some results.
Woad balls in a urine vat
Overall I think that the big issues we had with this one was that the vat wasn’t prepped far enough in advance, plus my friend and I are horribly impatient. We also forgot to test the ph of the vat.
This was another attempt with the urine vat that I tried last year. It had been topped up with fresh urine about 2 weeks before our attempt to dye.
The woad balls were crushed, mixed with warm water and then added into the urine vat. The vat was moved to a dye pot and warmed before we added the test swatch and skein and they were left for an hour.
When taken out, exposed to the air there was no change in colour. We left it out for a longer air exposure and there was still no change.
Woad powder and Thiourea Dioxide
We started with fresh water into a dye pot and then added woad powder and once it was brought up to the temperature we wanted added in the thiourea dioxide.
While we did manage to get blue from this method we were wondering why the dye bath didn’t have the yellow-green colour we had expected. I have since realized that this was because we didn’t test and then adjust the ph of the pot.
Searching for blue: Experiments with woad fermentation vats and an explanation of the colours through dye analysis